The subject matter disclosed herein relates to a turbomachine and, more particularly, to a method of operating a turbomachine to perform a fuel change over at a high load.
Typically, a turbomachine includes a compressor, a combustor and a turbine. The compressor compresses inlet gas to produce and output compressed gas. The combustor is fluidly coupled to the compressor to be receptive of the compressed gas and formed to define an interior in which the compressed gas is mixed with gas fuel and/or liquid fuel and combusted to produce a fluid flow of, for example, high temperature fluids. The fluid flow is then output from the combustor toward the turbine, which is formed to define a pathway through which the fluid flow is directed for power and/or electricity generation operations.
On heavy units equipped with dry low NOx (DLN) combustors, the liquid fuel (i.e., the distillate) is available as a backup fuel. In case of a problem with the gas fuel (i.e., the main fuel), the unit is transferred to the backup fuel. However, once the supply conditions are restored on the main fuel, the operator is required to reduce the load to a relatively low load, such as less than 30 MW or a relatively low power generation level depending on the turbomachine rating, in order to return to go back to the main fuel.